Carburretor Destruction

pave_spectre · November 21, 2009, 01:12:29 AM

Ok not really, but I did manage to destroy a few of the bolts holding the thing together.
Whoever decided to use cheap ass soft metal bolts should be slapped in the face with a brick.

Since I can't work on the bike due to a sever bout of clumsiness this week, I figured I'd post a few shots of the frustration of taking my carb apart to rejet.

1. What happened trying to remove one of the screws to get at the jet needles. It was originally a philips head, but stripped immediately, so I hit it with a cutting disc on my dremel and tried a flatblade. This is the end result, including where I had started to drill it out.

2. This is what left of the screw after I had drilled down part way then decided it was taking too long, and since I had removed the opposite screw just lifted the top of the carb and snapped it right on the line where i finished drilling. That left enough thread to be able to remove what was left by hand.

3. Since I couldn't reassemble the carb without screws (this wasn't the only one that got destroyed), I made a quick trip to Bunnings to see if I could find some replacements that would fit. Fortunately....

Could only find allen key bolts for the top, so had to go with philips head again for the jet covers underneath. All up I destroyed about six of the screws, 3 on top, and 3 underneath, turning what should have been a simple job of a few hours into about a 10 hour marathon over 2 days.

Thing now runs a tad rich, but not nearly as bad as before I replaced the air filter. Need to adjust the idle mixture, produces a slight smell of petrol out the exhaust. Before the air filter, when I turned it on first time after jetting, I wondered if I hadn't attached one of the fuel lines properly the smell was that bad.

Suspect I will have to replace the main jet as I believe I went way too rich, but won't know for sure as I haven't been able to take it for a ride since installing the K&N drop in filter, due to the aforementioned clumsiness leaving me unable to ride.

FatBastard · November 21, 2009, 01:24:23 AM

dear sweet baby Jesus, let this poor fellows fate, not be my own this week, when I have to take my bike apart, to do something similar amen

pave_spectre · November 21, 2009, 01:35:01 AM

Quote from: FatBastarddear sweet baby Jesus, let this poor fellows fate, not be my own this week, when I have to take my bike apart, to do something similar amen

I too, pray for anyone else that may wish to disassemble their carb, that they need not suffer the frustration and emotional pain that I did

black and silver twin · November 21, 2009, 02:06:44 AM

use an impact screw driver. it totals the screws, they get messed up any way, but it works every time and is fast and easy. when i jetted i used one on every screw knowing from this forum the stock screws suck then replaced them all with allen bolts. it is the best non-air tool ive bought besides socket set.

pave_spectre · November 21, 2009, 02:51:08 AM

Had I known beforehand the trouble I would experience, I probably would have taken the carb to work and borrowed an impact driver and a big hammer. or failing that some screw extractors. I looked at buying some screw extractors while I got replacement screws, but $70 was a bit steep.

sledge · November 21, 2009, 03:35:09 AM

Japanese industrial standard (JIS) screws are used to hold the carb together NOT Phillips. Use the correct tools and you wont have any problems and will save yourself a load of grief

http://www.ikaswebshop.com/hojisscset4d.html

kml.krk · November 21, 2009, 12:07:00 PM

fu..k that Japanese whatever screws + drivers

Phillips head is good enough if you know how to approach the problem

just smack the screws with the hammer, not directly the screw-head, but rather hit the screwdriver handle.
It always works and does not damage the screws.

Anyways, it is a good idea to replace those cheap screws with Allen bolts!

sledge · November 21, 2009, 12:20:58 PM

Remind me never to let you anywhere near my carbs

mister · November 21, 2009, 01:44:47 PM

Just found this...

Seems like a quick way to tell if you have JIS or not.

Michael

werase643 · November 21, 2009, 04:09:25 PM

small needle nose......MOLEGRIPS to un-tighten, then screwdriver always works for me

The Buddha · November 21, 2009, 04:45:43 PM

The screwdriver you use should bite in the head, and if you have it preloaded in either direction even slightly ... pulling it out should be very hard. I dont have a clue of late which is JIS and what isn't, but I fit the screwdriver in it and it has to bite ...
Cool.
Buddha.

pave_spectre · November 21, 2009, 05:50:38 PM

looking at what was left of a couple of the screws, i could see what might be a dimple, so probably they were JIS screws.
Could be wrong though as the dimple is barely bigger than a surface imperfection.

Quote from: The BuddhaThe screwdriver you use should bite in the head, and if you have it preloaded in either direction even slightly ... pulling it out should be very hard.

That's not really true for Philips or flat head screws as they are designed to cam out, whereas JIS as it turns out, are not, and philips are apparently known to destroy JIS.

If the dot were more than just a blemish I might have noticed it, chances are would have still gone about destroying them, cause f%$k getting speciality screwdrivers.

pave_spectre · November 28, 2009, 10:14:58 PM

For anyone who might be curious I appear to have solved the idle richness problem. Not sure about the rest of the rev range.
After trying a few adjustment on the idle mixture screw without noticeable change.
Turns out I was only running on one cylinder. One of the spark plug connectors was only sitting in place, which i discovered when i bumped it while adjusting the screw and it fell off. Put it back on more firmly, readjusted the mixture screws to three turns, where I had it originally, and no more petrol smelling exhaust.

PachmanP · November 29, 2009, 06:25:22 PM

Quote from: pave_spectre on November 28, 2009, 10:14:58 PM
For anyone who might be curious I appear to have solved the idle richness problem. Not sure about the rest of the rev range.
After trying a few adjustment on the idle mixture screw without noticeable change.
Turns out I was only running on one cylinder. One of the spark plug connectors was only sitting in place, which i discovered when i bumped it while adjusting the screw and it fell off. Put it back on more firmly, readjusted the mixture screws to three turns, where I had it originally, and no more petrol smelling exhaust.

Sweet! Always nice to run the twin on two cylinders!

As for the screws, yeah they're brass JIS. Basically, you just screw em up with a phillips and replace 'em with stainless phillips or allen. There is something to be said for using brass because then the screw goes before the threads in your carb, but if you're extra careful you'll be ok.

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Carburretor Destruction